<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>approach Axis</title>
    <style>
        #myBox{
            width: 200px;
            height: 200px;
            position: absolute;
            left: 50%;
            top: 50%;
            margin: -100px;
            background: mediumvioletred;
            text-align: center;
            overflow: hidden;
        }
        #targetMask{
            width: 200px;
            height: 200px;
            position: absolute;
            left: 100%;
            top: 0;
            color: whitesmoke;
            background: rgb(0,0,0);
            opacity: 0.5;
            filter:Alpha(opacity=50);
        }
    </style>
</head>
<body>
    <div id="myBox">
        <div id="targetMask">Mask</div>
    </div>
    <script src="approachAxis.js"></script>
    <script>
        var obj1=new MouseAxis('#myBox');
    </script>
</body>
</html>